/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.state;



import com.bff.gaia.unified.sdk.annotations.Experimental;

import com.bff.gaia.unified.sdk.annotations.Experimental.Kind;



/**

 * A {@link ReadableState} cell containing a set of elements.

 *

 * <p>Implementations of this form of state are expected to implement set operations such as {@link

 * #contains(Object)} efficiently, reading as little of the overall set as possible.

 *

 * @param <T> The type of elements in the set.

 */

@Experimental(Kind.STATE)

public interface SetState<T> extends GroupingState<T, Iterable<T>> {

  /** Returns true if this set contains the specified element. */

  ReadableState<Boolean> contains(T t);



  /**

   * Ensures a value is a member of the set, returning {@code true} if it was added and {@code

   * false} otherwise.

   *

   * <p>Elements added will not be reflected in {@code OutputT} objects returned by previous calls

   * to {@link #read}.

   */

  ReadableState<Boolean> addIfAbsent(T t);



  /**

   * Removes the specified element from this set if it is present.

   *

   * <p>Changes will not be reflected in {@code OutputT} objects returned by previous calls to

   * {@link #read}.

   */

  void remove(T t);



  @Override

  SetState<T> readLater();

}